You might also include a custom language phrase here, rather than hard-coding it.

In addition, you can override qa-include/pages/ask.php and qa-include/pages/question.php such that the language phrase gets updated and the error message gets added (if any) after ask.php:297 (when creating questions) and question.php:241 (when editing questions). You can check qa_set_up_name_field() to know what the form looks like.